Plaintain is very expensive in Gambia but don't send Plaintain to Gambia. Bitter Kola, Ogbono and egusi. By road you can go to Benin Republic and join bus to Bamako Mali then Dakar Senegal to Barr the Gambia boarder with Senegal then Ferry to cross you inside Banjul then to Sere Kunda market Gambia. Gambia don't have plaintain people bringing plaintain to Gambia from Conakry and Ghana.

It will be very expensive for you to travel with the bitter kola in same bus. You can take the bitter kola to trade fair where they load Gambia goods and join bus to Gambia Bitter kola, Ogbono and egusi are good to send to Gambia. Last time I traveled to Gambia by road was 2010 and 2013. It's about 5 days then I don't know for now. The bitter kola are buy by the Fulas in Sere Kunda market Gambia.